The invention pertains to methods of forming semiconductor structures, and in particular embodiments pertains to methods of forming capacitor electrodes and capacitor assemblies. The invention also encompasses capacitor structures, and capacitor-containing assemblies.
Capacitors are utilized in numerous semiconductor structures. For instance, capacitors can be coupled with transistors to form dynamic random access memory (DRAM) cells. A continuing goal in semiconductor device fabrication is to shrink the spacing between adjacent devices, and therefore enable an increasing number of devices to be formed within the same amount of semiconductor wafer real estate. A problem that can occur when spacing between adjacent capacitor structures is reduced is that various conductive components of the adjacent structures can extend across a gap between the structures, and ultimately cause an electrical short from one structure to an adjacent structure. Such electrical short can alter electrical characteristics associated with the capacitor structures, and even render the structures inoperable.
It would be desirable to develop new capacitor structures designed for relatively tight packing between adjacent structures; and it would be further desirable to develop methodologies for forming such structures.
In one aspect, the invention encompasses a method of forming a capacitor electrode. A sacrificial material sidewall is provided to extend at least partially around an opening. A first silicon-containing material is formed within the opening to partially fill the opening, and is doped with conductivity-enhancing dopant. A second silicon-containing material is formed within the partially filled opening, and is provided to be less heavily doped with conductivity-enhancing dopant than is the first silicon-containing material. At least some of the second silicon-containing material is converted into hemispherical grain silicon, and at least some of the sacrificial material sidewall is removed. The invention also encompasses methods of forming capacitors and capacitor assemblies incorporating the above-described capacitor electrode. Further, the invention encompasses capacitor assemblies and capacitor structures.
An exemplary capacitor structure encompassed by the invention comprises a container construction which includes a first silicon-containing layer around a second silicon-containing layer. The second silicon-containing layer defines an inner periphery of the container and the first silicon-containing defines an outer periphery of the container. At least some of the second silicon-containing layer is in the form of hemispherical grain silicon. A dielectric material is along the inner and outer peripheries of the container construction, and a conductive material is over the dielectric material. The container construction, dielectric material and conductive material together define at least part of the capacitor structure.